1. Technical Field
This improvement relates to valve and coupling devices used in pressure transfer lines for air or water that utilize a sliding control sleeve that vents to atmosphere in the off or open position.
2. Description of Prior Art
Prior art devices of this type have no specific safety lock-out feature and are directed to on and off positioning of the sliding control sleeve, see U.S. Pat. No. 1,850,879.
In U.S. Pat. No. 1,850,879 a valve and coupling assembly can be seen having a main tubular valve body with an inlet and an outlet port spaced by a partition therebetween. A plurality of aligned apertures extend annularly around the valve body adjacent either side of said partition. A control sleeve has a central, internal groove with oppositely disposed sealing rings attached thereto.